Well flow circulating methods

Claim 3

A method of manipulating a well tool in accordance with claim 1 including returning said well tool to the surface from said well by reversing the direction of flow of said fluid in said well passages comprising pumping said fluid into said second flow passage of said well displacing said well tool and fluid ahead of said well tool through said tubing string back to the surface while controlling the return fluid flow pressure ahead of said well tool to maintain the fluid pressure within said well at said optimum value.

Claim 4

A method of manipulating a well tool as defined in claim 2 in a production well including stabilizing said well preliminary to introducing said well tool into said tubing string by circulating liqUid through said well flow passages until said well is substantially filled with said liquid to develop a hydrostatic pressure in said well at least partially counterbalancing the bottom hole pressure of said well including flowing fluids returning from said well through a variable restriction and varying said restriction to limit the return fluid flow pressure from said well to a predetermined value for maintaining control of said well until production fluids in said well for passages are circulated out of said passages and replaced by said liquid.

Claim 5

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first string and up a second string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: maintaining said selected pressure on said fluid material in said formation by varying the back pressure on the fluid pumped up the second string in response to variations in the flow rate of fluid in said circulation path; a well tool being pumped through one of said strings by said fluid while said fluid is pumped through said circulation path; and thereby maintaining said selected fluid pressure on said formation.

Claim 6

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first string and up a second string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: maintaining said selected pressure on said fluid material in said formation by varying the back pressure on the fluid pumped up the second string in response to variations in the flow rate of fluid in said circulation path; a well tool being pumped through one of said strings by said fluid while said fluid is pumped through said circulation path; and thereby maintaining said selected fluid pressure on said formation.

Claim 7

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path.

Claim 8

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path.

Claim 9

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path; circulating fluid through the tubing string of the circulation path to provide a body of fluid of substantially uniform density in said tubing string of said circulating path; and pumping a well tool through one of said tubing strings by circulating said body of Fluid through said tubing strings.

Claim 10

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path; circulating fluid through the tubing string of the circulation path to provide a body of fluid of substantially uniform density in said tubing string of said circulating path; and pumping a well tool through one of said tubing strings by circulating said body of Fluid through said tubing strings.

Claim 11

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path; recording the pressure and flow rate of fluid pumped into said first tubing string; recording the pressure and flow rate of fluid flowing to the surface through said second tubing string; regulating the flow through the tubing strings in the well by maintaining a back pressure on the fluids flowing from the well at a value determined from the recordings to prevent flow of circulated fluids into the well formation and to prevent flow of fluids from the well formation into the circulated fluid in the circulation path.

Claim 12

In a well provided with at least two interconnected tubing strings providing a circulation path for fluid pumped down a first tubing string and up a second tubing string in which a fluid material is being held in a formation in communication with said well by application of a selected fluid pressure on said formation, the method which comprises: pumping fluid into said first tubing string at the surface downwardly in the well and upwardly from the well to the surface through said second tubing string; monitoring the pressure and flow rate of fluid pumped into said first tubing string at the surface; monitoring the pressure and flow rate of the fluids flowing from said second tubing string at the surface; determining from said monitored pressures and flow rates a back pressure to be applied to said fluids pumped through said tubing strings to maintain a selected fluid pressure on the fluid material in said formation; maintaining said selected fluid pressure back pressure on said fluid material in said formation by varying said back pressure at the surface on the fluid pumped up the second string determined in accordance with the monitored pressures and flow rates of the fluids in said circulation path; recording the pressure and flow rate of fluid pumped into said first tubing string; recording the pressure and flow rate of fluid flowing to the surface through said second tubing string; regulating the flow through the tubing strings in the well by maintaining a back pressure on the fluids flowing from the well at a value determined from the recordings to prevent flow of circulated fluids into the well formation and to prevent flow of fluids from the well formation into the circulated fluid in the circulation path.

Claim 15

A method of the character set forth in claim 8 including: recording the pressure and flow rate of the fluids pumped into said tubing string and the pressure and flow rate of fluids flowing to the surface through said second flow passage for use in controlling the pressure of return fluid flowing from said well.

Claim 16

A method of manipulating a well tool in accordance with claim 8 including: returning said well tool to the surface from said well by reversing the direction of flow of said fluid in said well passages by pumping said fluid into said second flow passage of said well displacing said well tool and fluid in said tubing string above said well tool through said tubing string back to the surface; controlling the pressure of the return fluid flowing ahead of said well tool to maintain the fluid pressure within said well at said desired value.

Claim 17

A method of manipulating a tool as defined in claim 8 including: stabilizing said well preliminary to introducing said well tool into said tubing string by circulating liquid through said well flow passages until said well is substantially filled with said lIquid to develop a hydrostatic pressure in said well at least partially counterbalancing the bottom hole pressure of said well; monitoring the pressure and flow rate of fluid pumped into said tubing string and the pressure and flow rate of fluid flowing to the surface through said second well flow passage; flowing fluids returning from said well through a variable restriction; and varying said restriction to limit the pressure of the return fluid flowing from said well to a predetermined value determined by said monitoring step for maintaining control of said well until production fluid in said well flow passages are circulated out of said passages and replaced by said liquid.

Claim 18

A method as set forth in claim 11 including: recording the pressures and flow rates monitored during the pumping of the fluids into the well and the flow of the fluid out of the well and varying the restriction for varying the flow of fluids from the well in accordance with the recorded monitored pressure and flow rates of fluids monitored and recorded.